package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
//id生成器
public class RedisIdWorker {
    /**
     * 开始时间戳
     */
    private static final long BEGIN_TIMESTAMP = 1672502400L;

    /**
     * 序列化的位数
     */

    private static final int COUNT_BITS = 32;

    @Resource
    private StringRedisTemplate stringRedisTemplate;


    public long nextId(String keyPrefix) {
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);//获取当前s数
        long timestamp = nowSecond - BEGIN_TIMESTAMP;//时间差值

        //2.生成序列号
        //获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyyy:MM:dd"));
        //自增长
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        //拼接返回
        return timestamp << COUNT_BITS | count;
    }

}
